In many applications for the transmission of electrical signals shielded cables are employed to in order to avoid interference between the signal transmitted by a particular cable with external signals such as signal transmitted by other cables. In particular, for the transmission of high frequency signals coaxial cables are a common type of shielded cables. A coaxial cable conducts the electrical signal using an inner conductor enclosed by a cylindrical sheath for shielding the conductor. Normally, the shield is kept at ground potential. In such coaxial design, the electric and magnetic fields can essentially be confined to the space between the inner conductor and the shield with little leakage outside the shield. Conversely, electric and magnetic fields outside the cable are largely kept from causing interference to signals inside the cable.
In order to connect coaxial cables in a way that leakage and interference is also avoided at the point of connection, coaxial connectors are frequently used. Typical coaxial connectors comprise a hollow cylinder of a plug of the connector, which when connected overlaps with a hollow cylinder of the socket of the connector to shield an inner conductor of the connector. It can be a drawback of such coaxial connectors that they are expensive to make, difficult to connect and less suited for a high number of mating cycles. The latter can be of particular disadvantage if an apparatus comprises interchange parts, which are frequently exchanged and which are attached to the apparatus by means of a coaxial connector. For example, many medical imaging apparatus comprise a selection of interchangeable imaging heads that are connected to a display unit or an application part via a coaxial cable and a coaxial connector. Such coaxial connector can be prone to fail due to frequent replacement of the imaging head. Moreover, it can be a drawback of conventional coaxial connectors that they require a considerable amount of space, which may, for example, entail high manufacturing costs, complicate handling and hamper miniaturisation.
In the prior art, it has been contemplated to replace the shield of a coaxial connector with a plurality of pins and sleeves. For instance, DE 101 64 799 B4 discloses an electrical connector for use with a cellular telephone wherein, in the plug, nine spring-loaded pins are arranged in three rows with three pins each. In each case, the central pin transmits a signal and the eight surrounding pins act as shields. Similarly, DE 199 45 176 B4 discloses an arrangement of spring-loaded contacts in which the signal transmitting contact in the centre is surrounded by four grounded contacts.
From KR 100275512 B1 an electrical connector is known which, in a first section, has alternating signal pins and ground pins. In a second section, for the transmission of a differential electrical signal groups of four signal pins in arranged in squares are separated by rows of ground pins so that each group of signal pins is surrounded by 8 or 12 ground pins. At the lateral sides of the connector, there are ground plates provided for shielding. KR 100275512 B1 suggests using the arrangement for connecting a motherboard to a daughterboard in an ATM switch via a backplane connection. A backplane connection in general does not need to withstand many mating cycles. Rather, it is connected upon assembly of the apparatus in which it is employed, and it typically is disconnected only if a faulty part of the apparatus needs replacement. Moreover, a backplane connection usually is not exposed to the outside of the apparatus but hidden inside the apparatus together with the apparatus' other internal components such as active electrical and electronic components. Moreover, a backplane connection is not a cable-cable connection and backplane connectors in general are unsuitable for cable-cable connections.